Auckland interceptor tenders submitted 27 Sep 2018

Watercare News Release

All four short-listed contractors have submitted tenders for construction of the 13km Central Interceptor wastewater tunnel that will run deep below Auckland. The four short-listed contractors had four months to prepare their tenders since the request for proposals was released in May and announcement of the successful contractor is expected in February 2019. Tenders from the four short-listed contractors are received from:

At 4.5m diameter, the new interceptor is the largest wastewater project ever undertaken in New Zealand. It will run up to 110m beneath the city to address wet-weather overflows into the harbour by diverting flow from the exisiting Eastern Interceptor and provide extra capacity to convey wastewater and stormwater from the Western Springs area to a new pump station at the Māngere wastewater treatment plant (Figs 1 and 2).

Figs 1 and 2. Route (left) and schematic of the 4.5m diameter interceptor tunnel to run up to 110m beneath the city

“The project is expected to reduce the volume of overflows into the city waterways and into the harbour by at least 80%,” said Chief Executive Raveen Jaduram of Watercare. “It will improve our environment as well as keep pace with the rapid growth of the city and provide time for Auckland Council to install stormwater sewers in areas where there are currently none.”

The project has been on the agenda for project owner Waterview for many years and its funding is already catered for in the company’s pricing plan. “It is part of the NZD $5.8 billion we will be spending on upgrading and expanding our infrastructure over the next decade,” said Jaduram.

Evaluating the tenders to identify a preferred bidder is expected to take about two months. Central Interceptor Executive Programme Director Shayne Cunis said that stringent probity measures are being taken to protect the tender process. “These security measures are in line with what would be expected of a project of this scale,” said Cunis. “It is a big undertaking, and the contractors have put a lot of time and resource into their tenders. We will ensure our process for protecting their submissions is watertight.”

Following announcement of the successful contractor, construction is scheduled to begin next year and continue until 2025.

“All four groups have demonstrated that they have the ability and experience to deliver this project to the required standard, while adding significant value to the project;” said Shayne Cunis, Executive Programme Director for the Central Interceptor.

Central Interceptor alignment in Auckland

“We are looking forward to working with them on the next stage of the process and remain committed to meeting our timeframes for delivery of the Central Interceptor for the people of Auckland.”

Design and technical documentation will be released in March, and the Request for Proposal will be issued to the short-listed contractors in May.

The 13km long x 4.5m diameter tunnel is designed to help reduce combined wastewater and stormwater overflows to local waterways and the Waitemata Harbour due to a growing population in Auckland. It is expected to reduce overflows by 80%.

The tunnel will run from Western Springs to Mangere Wastewater Treatment Plant at a depth of between 22m and 110m, connecting existing networks along the route via link sewers and will include 17 shafts at 16 locations. It will then cross 15m below the seabed at Manukau Harbour where it will replace an older deteriorating pipeline and provide scope for future development.

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